Let-off mechanism for looms



Mar. 3, 1925. 1,528,579

A. E. STAFFORD I LET-OFF MECHANISM FOR LOOKS Filed May 1"7 9 lnven'ror.

Alfred ESTufFord MMKM AWysQ Patented Mar. 3, 1925.

UNITED STATES PATENT OFFICE.

ALFRED E. STAFFORD, OF HOPEDALE, MASSACHUSETTS, ASSIGNOR TO DRAPER COR- PORATION, 0F HOPEDALE, MASSACHUSETTS, A CORPORATION OF MAINE.

LET-OFF MECHANISM. FOR LOOMS.

Application filed May 17, 1924. Serial No. 714,178.

To all whom it may concern:

Be it known that I, ALFRED E. STAFFORD, a citizen of the United States, and a resident of Hopedale, county of Worcester, State of Massachusetts, have invented an Improvement in Let-Off Mechanism for Looms, of which the following description, in connection with the accoi'npanying draw ing, is a specification, like characters on the drawing representing like parts.

This invention relates to let-o5 mechanism for looms particularly of that. type shown in the patent to Draper and Roper, No. 647,815, granted April 17, 1900, which is well known and familiar to those skilled in the weaving art.

The object of the invention is to provide a construction which will prevent longitudinal movement of the main shaft of the let-off mechanism and thus insure the elements of the mechanism rotatable or mounted thereon maintaining their proper relation.

The object of the invention is furtl'ier to provide means for preventing a pinion carried by the main shaft of the let-oil mechanism from shifting into contact with and injuring the warp beam head.

The object of the invention is further to provide for the free oscillation of the actuat j a hub 15 rotatable on the'shaft 3 and the ing pawl carrier of the let-off mechanism.

These and other objects and features of the invention will appear more fully from the accompanying description and drawings and will be particularly pointed out in the claims.

As the general type of mechanism to which this invention relates is well known and familiar to those skilled in this art it will only be necessary to illustrate and describe the parts of the let-ofi mechanism immediately concerned with the present invention. Reference is made to the above mentioned patent to Draper and Roper for a fuller illustration of the let-off mechanism in which the preferred form of the present invention has been embodied.

The sole figure of drawing shows, therefore, a fragmentary portion of the 100m and let-ofi' mechanism partially in elevation and partially in central vertical cross section.

In this type of let-off mechanism, as shown in the Draper and Roper patent, an

elongated hub bearing 1 is rigidly secured thereto.

to, formed on, or mounted on, a vertical member such as the side frame 2 of the loom. In this hub bearing is mounted the main or pinion shaft 3 of the let-off mechanism. This shaft at its inner end has rigidly secured thereto by a set screw. the hub 5 of a pinion 6. Tris pinion 6 intermeshes with a gear secured to thewarp beam 8 adjacent the head of the warp beam.

The opposite end of the shaft 3 has rigidl secured thereto as b a set screw 10 the hub 11 of an element 12 of the mechanisnn which serves to drive the shaft 3. This element 1?. is, in the type of mechanism illustrated, a gear having internal teeth 13.

The peculiar and desired let-off rotation of the shaft 3 is secured in this construe tion by elements which include a ratchet wheel, a pawl carrier and pawl co-operat The ratchet wheel 14 is provided with exterior surface 16 of this hub is eccentric to the axis of rotation. Upon this eccentric surface 16 of the hub 15 of the ratchet wheel 14 is rotatably mounted a gear 17 which is held against rotation, which has a less number of teeth than the teeth 13 of the gear 12 and which intermeshes with the teeth of the gear 12. The pawl 18 is mounted upon a pawl carrier 19 also ro-' tatable with respect to the shaft 3 and having an oscillatory rotary movement with respect to the shaft to effect the movement of the ratchet wheel 14.

In this type of mechanism great difiiculty has been experienced in maintaining the longitudinal position of the shaft 3 and consequently of the pinion 6 which is secured The wear of the different elements particularly permits the shaft 3 to shift or move. longitudinally with the result that the pinion 6 chews into the head 9 of the -warpbeam injuring the warp beam, injurmg the pinion and interfering with the proper functioning of the mechamsm.

In the present invention a bushing 20 is rotatably mounted on the shafts and on this bushing is rotatably mounted the hub 21 of the pawl carrier 19 and this bushing is madeof such a length as to f 1 the other elements an inter-posing means be tween the hub 5 of the pinion 6 and the gear 12 which prevents longitudinal movement of the shaft 3.

In the construction illustrated the hub 5 of'the pinion 6 abuts against the inner end of the hub bearing 1 which hub bearing is tiredagainst long"udinal movement; the bushing 20 abuts against the other end of the hub bearing 1; the hub 15 of the ratchet wheel abuts at one end the bushing and at the other end the gear 12. lhe shaft 3 and the ratchet wheel 14- rotate very.

slowly and the bushing 20 which is preferably free from connection with either the hub bearing or the ratchet wheel 14 also has a very slight movement, if any as it may remain stationary or rotate with the ratchet wheel 14: or rotate to a less 'de gree. There isthuspractically no wear which tends to effect the length of the parts interposed between the pinion ti and the gear 12 and consequently any longitudinal movement of the shaft 3 and pinion 6 is effectively prevented.

The pawl carrier 19 has a con .nt oscillatory or rotary movement and is made with a loose fit between the end of the hub hearing '1 and the end of the hub 15 of the ratchet wheel. As this element has the greatest amount of movement and thrmovement is constant it willvbe subject to the great-est amount of wear but as it forms no part of the means interposed between the pinion 6 and gear 12 for preventing longitudinal movement of the shaft any such wear has no effect upon the longitudinal position of the shaft.

There is thus provided a very simple and effective means for securing the desired result and one that may be readily applied to existing let-off mechanisms.

Having thus described the invention what is claimed as new and desired'to be secured by Letters Patent, is:

1. A let-0'5 motion for looms comprising a hub bearing on the loom frame, a shaft journaled in the hub bearing, a pinion se cured to the shaft and abut-ting one end of the hub bearing,a bushing rotatable on the shaft and abutting the other end of the hub bearing, a ratchet wheel having a hub rotatable on the shaft abutting at one end the other end of the bushing, a gear secured to the shaft and abuttingt he other end of the ratchet wheel hub, and'a pawl carrier rotatable on the bushing and having a loose lit between the hub bearing and the ratchet wheel hub whereby the development of wear or lost motion between the pawl carrier and the bushing or between it and the hub hearing and ratchet wheel hub cannot affect the longitudinal position of the shaft and pinion and whereby the free oscillation of the pawl carrier cannot be impeded by the hub bearing and ratchet wheel hub.

2. A let-off motion for looms comprising a. hub bearing on the loom frame, a. shaft journaled in the hub bearing, a pinion secured to the shaft, a driving element for the shaft secured thereto, means on the shaft, including a rotatable bushing and the said hub bearing, interposed between the pinion and the driving element andacting to prevent longitudinal movement of the shaft and a movable element rotatable on the bushing and having a loose fit between the hub bearing and the driving element.

In testimony whereof, I have signed my name to this specification.

ALFRED E. STAFFORD. 

